Erectile dysfunction occurs extensively among patients with arterial hypertension. We investigated the safety of sildenafil for patients with and without antihypertensive medication. Our study included data from 35 double-blind, placebo- controlled, and randomized investigations, with a total of 8115 patients. The term of therapy was between 6 weeks and 6 months, for both the sildenafil group (5-200 mg, n = 4819) as well as the placebo group (n = 3296). We studied the adverse events in the men who received 1 or more hypertensives (n = 2388), and in those who took no antihypertensive medication (n = 5727). Our findings disclosed equal frequency of adverse events in both groups, without influence by the number of different antihypertensives administered. The occurrence of AEs associated with blood pressure was slight, and was comparable between the individual groups. These results support the conclusion that sildenafil is also well tolerated by patients taking one or more antihypertensives. Patients being treated with alpha blockers should be stable on this therapy in order to minimize the possibility of orthostatic hypotension. An initial dose of 25 mg should furthermore be considered for these patients.